Cyclic Sulfur Oxide Electrolyte Additive for Stable Battery SEI
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Solution Overview
Problem
Lithium secondary batteries face performance degradation due to the collapse of the solid electrolyte interface (SEI) at high temperatures, leading to irreversible reactions and battery swelling, which affects cycle stability and storage characteristics.
Innovation Solution
A non-aqueous electrolyte solution additive with a cyclic sulfur oxide structure is used to form a stable SEI, reducing interfacial resistance and preventing electrode surface exposure, thereby enhancing high-temperature storage and cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte solutions are used, then initial battery performance is achieved, but SEI collapse occurs at high temperatures leading to performance degradation
Solution Approach 1:
The patent introduces a novel cyclic sulfur oxide compound with specific molecular structure parameters (Formula 1) that changes the chemical composition parameters of the electrolyte solution. This compound forms an SEI with different physical-chemical properties (lower resistance, higher stability) compared to conventional SEI, resolving the contradiction between initial performance and high-temperature stability
Solution Approach 2:
The patent creates a composite SEI structure by combining the novel cyclic sulfur oxide compound with existing electrolyte components (lithium salts, solvents). This composite approach allows the SEI to inherit beneficial properties from multiple components, achieving both low resistance and high-temperature stability simultaneously
2Duration of action of moving object
If charge and discharge cycles proceed, then battery operation is maintained, but positive electrode active material structurally collapses
Solution Approach 1:
The cyclic sulfur oxide compound performs preliminary action by forming a protective SEI film on the electrode surfaces before structural collapse can occur. This pre-formed SEI acts as a protective barrier that prevents metal ion dissolution and electrodeposition during subsequent charge-discharge cycles, maintaining electrode structural integrity
Solution Approach 2:
The SEI formed by the cyclic sulfur oxide compound serves as an intermediary layer between the electrolyte and electrode materials. This intermediate layer prevents direct harmful interactions while allowing beneficial lithium ion transport, thereby protecting the positive electrode active material from structural collapse during cycling
3Reliability
If additive decomposes during initial charge and discharge, then SEI film is formed, but irreversible capacity is consumed
Solution Approach 1:
The patent modifies the chemical parameters of the additive (using cyclic sulfur oxide structure) to change the decomposition behavior. The modified additive forms a more efficient SEI that requires less lithium ion consumption during formation, reducing irreversible capacity while still achieving reliable battery characteristics
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The additive improves battery lifetime by forming a robust SEI with low resistance, reducing gas generation and maintaining stable performance under high-temperature conditions.
Implementation Method 1
the additive may be decomposed during initial charge and discharge to form a film called a solid electrolyte interface (SEI) on the surface of the electrode
Implementation Method 2
acts as an ion tunnel that selectively passes only the lithium ions between the electrolyte solution and the negative electrode
Implementation Method 3
The SEI prevents collapse of a carbon-based negative electrode structure by blocking movement of organic solvents of the electrolyte solution having a large molecular weight to the carbon-based negative electrode due to the ion tunnel effect
Data Source
AI summary
The present invention relates to a compound having a cyclic sulfur oxide structure, and a non-aqueous electrolyte solution additive, a non-aqueous electrolyte solution, and a lithium secondary battery which include the same, wherein the lithium secondary battery of the present invention may achieve improved effects in terms of high-temperature stability and gas generation while being able to achieve stable performance for a long time.